Eight bogies of a goods train were derailed in another blast at around 9.30 pm on the railway track near Ultapool between Digboi and Tinsukia. The driver of the train was injured. “The coal-laden train was coming from Ledo,” superintendent of police Tangkha said.

The first explosion rocked the main grocery wholesale market in the Chamber Road area here at 11.45 am.

Those wounded were taken to the Tinsukia civil hospital, but five of the critically injured were shifted to the Assam Medical College and Hospital in Dibrugarh.

Most of the injured are porters, cart-pullers or small-time businessmen.

One of the injured, Surbanshi Rai, who is undergoing treatment in the civil hospital, said he heard a loud bang before he was flung to the ground. “Bahut jor ka dhamaka hua, uske baad sab log chillaney aur daurney lagey (there was a big sound and people started shouting and running after that).”

The district police, who have been on their toes since the grenade attacks inside the cinema hall here and a hardware store in Doom Dooma a couple of days back, said a patrol party had cleared the traffic from the busy area hardly an hour before the explosion.

Blaming the Ulfa for the blast, Tinsukia superintendent of police Anurag Tangkha said the militants brought the IED in a gunny bag on a bicycle to the blast site. They later abandoned the cycle. “We have recovered it some 100 metres away from the spot along with pieces of the gunny bag”, he added.

“They (the Ulfa militants) are desperate to prove that they are still up and running after the setback in Bhutan. This is why they are unleashing such violence on the common people. However, we have tightened security arrangements in the district,” the police official said.

Inspector general of police (law and order) D.K. Pathak said in Guwahati the police were trying to ascertain the involvement of the banned Ulfa in the blast.

Pathak, who will be reaching Tinsukia tonight, said a massive combing operation has been launched to hunt down the militants. “We have a strong suspicion that a section of scattered militants are behind the recent spate of violence in the district to create panic among the people,” he added.

As many as 21 people were injured in the cinema hall attack, one of whom died at the AMCH in Dibrugarh the very next day.

Sources said the police were hopeful that Ulfa militant Sunanda Gogoi, who was arrested in Bordubi two days ago, could provide some clues on today’s blast.